DESC:FIELD OF INVENTION
[0001] The present disclosure relates generally to a serial data communication. The disclosure, more particularly, relates to a method for polarity insensitive communication over differential signal transmission in half-duplex mode.

BACKGROUND
[0002] In conventional communication systems, twisted cables are used for connecting the equipment’s in a network. These twisted cables are cheaper, less susceptible to noises and are easy to splice and maintain. Also, the colour coding on the wires determines the polarity of the connected nodes. Further, there are receivers that will receive inverted or non-inverted data, based on the polarity connection. In such environments, it becomes difficult to maintain and connect the wires based on the colour codes. In such communications, the master/slave communication mode is commonly used due to hierarchical command structure and for achieving reliability.
[0003] In one of the conventional systems as shown in Figure 1, it illustrates a block diagram of a central computing unit and a receiver, according to an exemplary implementation of the present disclosure. It illustrates a line communication system with twisted cables that comprises of a central computing unit and the receiver or receiver terminals which act as a computing system. The data transmission between the central computing unit and the receiver terminals is done with a two-wire wiring system using the serial data with differential signal transmission technology. The central computing unit acts as a master node and the receiver terminals act as slave nodes in the serial data transmission and reception modes. During the transmission or reception of the data between the central computing unit and the receiver terminals, the central computing unit hardware is configured to control the differential line at its end to either enter into transmit or receive mode as shown in Figure 2a. The Figure 2a is a schematic diagram depicting a star network configuration, according to an exemplary implementation of the present disclosure.
[0004] In another conventional implementation as shown in Figure 2b, it illustrates a schematic diagram depicting a daisy chain network configuration, according to an exemplary implementation of the present disclosure. Here, the two-wires connected at the central computing unit having say polarity “X” with line 1 and line 2 have to be connected to polarity “X” with line 1 and line 2 at the receiver terminals endpoints. In any conventional system, it has been a problem that, when this connection is reversed, say polarity “Y” where line 1 and line 2 wires have been exchanged, the normal data transmission operation becomes impossible, as the receiver terminals do not understand the data received at their end due to reversed polarity. For example, Receiver #4 in Figure 2a and Figure 2b are connected on reverse polarity.
[0005] US005257160A titled “Serial signal transmission device and control method for determining polarity”, describes the serial signal transmission device which carries out signal transmission between a plurality of control devices using two transmission wires with fixed polarity, the serial transmission interface of each control device is equipped with two pairs of differential drivers and receivers, and the driver outputs and receiver inputs of different polarity in these two pairs of drivers and receivers are connected to each other. According to the serial signal transmission device, it becomes possible to transmit signals properly, for example, by including a function of switching the polarity of signal wires in a serial transmission interface of each control device and by choosing a driver and a receiver with correct polarity from two pairs of drivers and receivers having different polarity. The polarity of each signal transmission device is adjusted by transmitting, a random number of times and between signal transmission devices, data packets containing data as to whether polarity has been determined and whether the polarity is in order or in reverse and data expressing the address number for identifying each signal transmission device while alternating their polarity, with their polarity in order or in reverse, so as to make each other's polarity in agreement, and a signal transmission device with undetermined polarity adjusts its polarity to make it coincide with that of another signal transmission device with determined polarity. According to the above method, by transmitting data packets between each other, the polarity of a device with undetermined polarity is adjusted to coincide with that of a device with determined polarity provided there are two pairs of differential drivers and receiver outputs.
[0006] US4807261 titled “Automatic channel polarity detection and correction arrangement and method”, describes a receiver circuit which can automatically detect and correct channel polarity inversions in a FSK communication system employing grey code symbol assignments. A method for decoding data received in a receiver wherein the data is coded in symbols which are represented by a grey code-like numbering system and the data includes a predetermined word sync pattern and step of automatically correcting includes the step of inverting the identified common bit in the data. According to the above method, with receiver circuit, the polarity inversion is corrected based on grey-code like numbering system and sync pattern in the data itself.
[0007] Therefore, there is still a need of an invention which solves the above defined problems and provides a method therein the connected nodes in a communication system should be able to communicate even with the interchanged polarity connections in wires.

SUMMARY
[0008] This summary is provided to introduce concepts related to a system and method for determining polarity of one or more receivers over differential signal transmission in a half-duplex mode. This summary is neither intended to identify essential features of the present invention nor is it intended for use in determining or limiting the scope of the present invention.
[0009] In an embodiment of the present invention, a method for determining polarity of one or more receivers over differential signal transmission in a half-duplex mode is disclosed. The method includes maintaining the polarity information of the one or more receivers for polling by a central computing unit. Here, the one or more receivers includes first receiver and the second receiver. Further, the method includes initiating a data communication with one or more receivers for a plurality of cycles by the central computing unit. Further, sending a REQ command to the one or more receivers in the first cycle by the central computing unit. Here, the one or more receivers are selected through polling before sending the REQ command to one or more receivers in the first cycle. The method further includes responding with a RESP command by one or more receivers to the central computing unit. These one or more receivers are connected with same polarity. updating, by the central computing unit, the polarity information of the responded receivers. Further, the method includes identifying the one or more receivers that fail to respond with a RESP command to the central computing unit. Further, it includes reversing the polarity of the central computing unit for sending the data to one or more receivers connected with reverse polarity in the subsequent cycle and updating the polarity information of the receivers with their polarity by the central computing unit.
[0010] In another embodiment of the present invention, a system for determining polarity of one or more receivers over differential signal transmission in a half-duplex mode is provided. The system includes a memory and a central computing unit coupled with the memory. The central computing unit maintains the polarity information of the one or more receivers for polling. It further initiates a data communication with one or more receivers for a plurality of cycles and sends a REQ command to the one or more receivers in the first cycle. Further, the system includes one or more receivers that respond with a RESP command to the central computing unit. Here, the one or more receivers are connected with same polarity. Further, the central computing unit updates the polarity information of the responded receivers. Further, one or more receivers that fail to respond with a RESP command to the central computing unit are identified and the polarity of the central computing unit is reversed for sending the data to one or more receivers connected with reverse polarity in the subsequent cycle. Furthermore, the central computing unit updates the polarity information of the receivers with their polarity.

BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
[0011] The detailed description is described with reference to the accompanying figures.
[0012] Figure 1 illustrates a block diagram of a central computing unit and a receiver, in accordance with an embodiment of the present invention.
[0013] Figure 2a illustrates a schematic diagram depicting a star network configuration, in accordance with an embodiment of the present invention.
[0014] Figure 2b illustrates a schematic diagram depicting a daisy chain network configuration, in accordance with an embodiment of the present invention.
[0015] Figure 3 illustrates a schematic diagram of a dual polarity (master slave) connections, in accordance with an embodiment of the present invention.
[0016] Figure 4 illustrates a schematic diagram of a plurality of packet structures, in accordance with an embodiment of the present invention.
[0017] Figure 5 illustrates a schematic diagram of a timing diagram in a half-duplex mode, in accordance with an embodiment of the present invention.
[0018] Figure 6 illustrates a flowchart of a state diagram in half-duplex mode, in accordance with an embodiment of the present invention.
[0019] Figure 7 illustrates a flowchart of the receiver flow, in accordance with an embodiment of the present invention.
[0020] Figure 8 illustrates a flowchart of the process of polarity discovery, in accordance with an embodiment of the present invention.
[0021] Figure 9 illustrates a flowchart of an adjacent polarity handling, in accordance with an embodiment of the present invention.
[0022] Figure 10 illustrates a flowchart of another embodiment of a method for determining polarity of one or more receivers over differential signal transmission in a half-duplex mode, in accordance with an embodiment of the present invention.
[0023] It should be appreciated by those skilled in the art that any block diagrams herein represent conceptual views of illustrative systems embodying the principles of the present invention. Similarly, it will be appreciated that any flow chart, flow diagram, and the like represent various processes which may be substantially represented in computer readable medium and so executed by a computer or processor, whether or not such computer or processor is explicitly shown.

DETAILED DESCRIPTION
[0024] The various embodiments of the present invention provides a system and method for determining polarity of one or more receivers over differential signal transmission in a half-duplex mode.
[0025] In the following description, for purpose of explanation, specific details are set forth in order to provide an understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without these details.
[0026] One skilled in the art will recognize that embodiments of the present invention, some of which are described below, may be incorporated into a number of systems.
[0027] However, the device is not limited to the specific embodiments described herein. Further, structures and devices shown in the figures are illustrative of exemplary embodiments of the present invention and are meant to avoid obscuring of the present invention.
[0028] Furthermore, connections between components and/or modules within the figures are not intended to be limited to direct connections. Rather, these components and modules may be modified, re-formatted or otherwise changed by intermediary components and modules.
[0029] The appearances of the phrase “in an embodiment” in various places in the specification are not necessarily all referring to the same embodiment.
[0030] In an embodiment of the present invention, a method for determining polarity of one or more receivers over differential signal transmission in a half-duplex mode is disclosed. The method includes maintaining the polarity information of the one or more receivers for polling by a central computing unit. Here, the one or more receivers includes first receiver and the second receiver. Further, the method includes initiating a data communication with one or more receivers for a plurality of cycles by the central computing unit. Further, sending a REQ command to the one or more receivers in the first cycle by the central computing unit. Here, the one or more receivers are selected through polling before sending the REQ command to one or more receivers in the first cycle. The method further includes responding with a RESP command by one or more receivers to the central computing unit. These one or more receivers are connected with same polarity. updating, by the central computing unit, the polarity information of the responded receivers. Further, the method includes identifying the one or more receivers that fail to respond with a RESP command to the central computing unit. Further, it includes reversing the polarity of the central computing unit for sending the data to one or more receivers connected with reverse polarity in the subsequent cycle and updating the polarity information of the receivers with their polarity by the central computing unit.
[0031] In another embodiment of the present invention, a system for determining polarity of one or more receivers over differential signal transmission in a half-duplex mode is provided. The system includes a memory and a central computing unit coupled with the memory. The central computing unit maintains the polarity information of the one or more receivers for polling. It further initiates a data communication with one or more receivers for a plurality of cycles and sends a REQ command to the one or more receivers in the first cycle. Further, the system includes one or more receivers that respond with a RESP command to the central computing unit. Here, the one or more receivers are connected with same polarity. Further, the central computing unit updates the polarity information of the responded receivers. Further, one or more receivers that fail to respond with a RESP command to the central computing unit are identified and the polarity of the central computing unit is reversed for sending the data to one or more receivers connected with reverse polarity in the subsequent cycle. Furthermore, the central computing unit updates the polarity information of the receivers with their polarity.
[0032] In another embodiment, a method for managing the polarity of the adjacent one or more receivers is provided. The method includes verifying the polarity of the second receiver by the central computing unit if no data is to be sent. Further, the REQ command is sent with the second receiver’s polarity. And after that the availability of the data is verified for transmitting from the central computing unit to the first receiver. Further the data and the REQ command are sent in the first receiver’s polarity. The first receiver receives and processes the data from the sent data and the REQ command and discards the REQ command as it is meant for second receiver Then the data and the REQ command are sent in second receiver’s (reverse) polarity as meant for. Furthermore, the second receiver receives and processes the REQ command from the sent data and the REQ command. Upon which the second receiver responds with the RESP command.
[0033] Further, the method further includes a pair of differential serial transmission lines for transmitting signals in the half duplex mode between a central computing unit and one or more receivers wherein each of the receivers has a serial interface with the connected pair of differential serial lines transmission.
[0034] Further, the method includes verifying by the central computing unit the destined node identifier once said receiver receives the REQ command; and responding with a RESP command by the receiver to the central computing unit once the destined node identifier matches with the identifier of the receiver. Further, the REQ command is discarded when the destined node identifier fails to match with the identifier of the receiver.
[0035] Furthermore, the REQ command sent to the receiver in the first cycle is of positive polarity and the REQ command is sent in negative polarity in the subsequent cycle for said receiver for detecting another receiver.
[0036] In another embodiment, a method of automatic detection of the polarity of the connected receivers with that of the central computing unit in serial data transmission using said method is provided. This method comprises of a central computing unit that acts as master and is configured to control the communication channel throughout the lifecycle. It further comprises a receiver or plurality of receiver terminals that act as slaves and is configured to respond or process only to the query or data received from the central computing unit in a half-duplex mode.
[0037] In another embodiment , the connected nodes in the network can be setup in two configurations using one pair of twisted cables such as a star network configuration as shown in Figure 2a and a daisy chain network configuration as shown in Figure 2b, respectively.
[0038] In another embodiment, the central computing unit is configured to initiate the communication and send a REQ command to the plurality of chosen receivers through polling, the central computing unit is then configured to wait for a specified timespan for the intended receiver’s response.
[0039] In another embodiment, the receiver, that is connected with the same polarity, is configured to respond with RESP command to the central computing unit.
[0040] In another embodiment, the central computing unit is configured to keep a track of the discovered receivers with their polarity status. Further, it assumes a receiver’s nonexistence in the network, in case if the receiver does not respond with RESP command within the specified timespan.
[0041] In another embodiment, after every cycle, one undiscovered receiver gets its polling cycle again to respond with RESP command. Only the receivers that respond are discovered as they communicate with the same polarity as that of the central computing unit. To discover the receivers connected with different polarity, the central computing unit is configured to invert its data in the subsequent alternate cycles expecting the undiscovered receivers to respond.
[0042] In another embodiment, the central computing unit is configured to maintain the polarity information and to continue polling for receivers with their learned polarity for their responses.
[0043] In another embodiment, a method is provided to handle communication in the mixed polarity communication in connected nodes associated with differential serial transmission. To meet the communication requirements, the discovery of polarity with the connected nodes are handled at the central computing unit. The polarity insensitive technique deals with the problem of polarity mismatch among connected nodes and ensure seamless communication of the networked nodes using this customized communication protocol.
[0044] Figure 3 illustrates a schematic diagram of a dual polarity (master slave) connections, according to an exemplary implementation of the present disclosure. The central computing unit (302) acts as a master node and the one or more receivers (304, 306, 308) act as slave nodes in the serial data transmission and reception modes. The one or more receivers includes first receiver (304), second receiver (306) and a third receiver (308).To realize the polarity of the connected nodes, the central computing unit (302) is configured to maintain a status of polarity of the connected nodes i.e. the receivers (304, 306, 308). The data differential signal pins are reversed to achieve polarity insensitive as shown in this figure.
[0045] Figure 4 illustrates a schematic diagram of a plurality of packet structures, according to an exemplary implementation of the present disclosure. A plurality of information of the control packet structure such as the header, source id, destination ID and the like are maintained. Further, the plurality of information of the control packet structure along with data packet structure such as the header, source id, destination ID, data about the packets and the like are maintained.
[0046] Figure 5 illustrates a schematic diagram of a timing diagram in a half-duplex mode, according to an exemplary implementation of the present disclosure. In the timing diagram, Q[n] implies the query packet same polarity, ~Q[n] implies query packet inverse polarity, R[n] implies reply packet, D[n] implies data packet, Recv#1 implies same polarity and Recv#2 implies reverse polarity. The below mentioned steps are depicted in the timing diagram. It demonstrates a method of automatic detection of the polarity of the connected receivers (304, 306, 308) with that of the central computing unit (302) in serial data transmission using said method is provided. This method comprises of a central computing unit (302) that acts as master and is configured to control the communication channel throughout the lifecycle. It further comprises a receiver or plurality of receivers (304, 306, 308) that act as slaves and is configured to respond or process only to the query or data received from the central computing unit (302) in a half-duplex mode. Further, the connected nodes in the network can be setup in two configurations using one pair of twisted cables such as a star network configuration as shown in Figure 2a and a daisy chain network configuration as shown in Figure 2b, respectively.
[0047] Furthermore, the central computing unit (302) is configured to initiate the communication and send a REQ command to the plurality of chosen receivers (304, 306, 308) through polling, the central computing unit (302) is then configured to wait for a specified timespan for the intended receiver’s response. The receiver, that is connected with the same polarity, is configured to respond with RESP command to the central computing unit (302). The central computing unit (302) is configured to keep a track of the discovered receivers (304, 306, 308) with their polarity status. Further, it assumes a receiver’s nonexistence in the network, in case if the receiver does not respond with RESP command within the specified timespan. After every cycle, one undiscovered receiver gets its polling cycle again to respond with RESP command. Only the receivers (304, 306, 308) that respond are discovered as they communicate with the same polarity as that of the central computing unit (302). To discover the receivers (304, 306, 308) connected with different polarity, the central computing unit (302) is configured to invert its data in the subsequent alternate cycles expecting the undiscovered receivers (304, 306, 308) to respond. The central computing unit (302) is configured to maintain the polarity information and to continue polling for receivers (304, 306, 308) with their learned polarity for their responses.
[0048] Figure 6 illustrates a flowchart of a state diagram in half-duplex mode, according to an exemplary implementation of the present disclosure. The first state is a comm-idle state which is the state after power on. In this state, the central computing unit (302) is configured to initialize the data structures and various variables to their default state. The second state is a comm-transmit data state which is a fixed duration state, configurable at a designed time for which the central computing unit (302) is configured to attempt to transmit the data. The computing unit then waits for a duration equivalent to 1000ms to check for any received packets from an already discovered receiver or 2000ms for an undiscovered receiver. Further, the third state is a comm-process data state wherein the central computing unit (302) is configured to update the receiver’s polarity status based on the receive packet counter from a particular receiver. In case, the central computing unit (302) does not receive any packet during the wait duration, it is configured to increment the receive packet counter. If the receive packet counter exceeds cycles and the central computing unit (302) does not receive any acknowledgment from the receiver, it removes the receiver from the network. Furthermore, it processes the data received from the receiver and switches back to the first state which is the comm-idle state, respectively. Further, the fourth state is a comm-transmit reverse state wherein the central computing unit (302) is configured to transmit data in reversed polarity (inverted data) to get the responses from the undiscovered receivers (304, 306, 308).
[0049] Figure 7 illustrates a flowchart of the receiver flow, according to an exemplary implementation of the present disclosure. Here, the receiver is configured to receive the control packet and to check destined node identifier. If the destined identifier matches the identifier of the receiver node, it sends the response (RESP) control packet to the central computing unit (302). If it is not meant for the receiver node, the packet is discarded. Further, when the receiver is configured to receive the data packet, it checks the destined node identifier. If the destined identifier matches the identifier of the receiver node, it is processed but no response (RESP) packet is sent. If it is not meant for the receiver node, the packet is discarded.
[0050] Figure 8 illustrates a flowchart of the process of polarity discovery, according to an exemplary implementation of the present disclosure. The methodology of discovering the polarity of the receivers (304, 306, 308) is described herein. The central computing unit (302) (CCU) is configured to maintain a plurality of Initializing (INIT) structures comprising of POLARITY(1…n) and ALIVE(1…n) that keeps a track of the receiver’s polarity information and availability information, respectively. Initially, CCU assumes that all the receivers (304, 306, 308) are switched on and responsive and ALIVE (1…n) is set for all receivers (304, 306, 308) and the communication starts. The CCU is configured to initiate the communication cycle and to send CTRL packet (REQ) command to the receivers (304, 306, 308) through polling, then to wait for specified time for the intended receiver’s response. The receiver which is connected with same polarity responds with CTRL packet (RESP) command to the central computing unit (302) only when the destined node identifier matches with the receiver’s identifier else the packet is discarded. Then the CCU updates the POLARITY (1…n) status of those receivers (304, 306, 308) which had responded. This step is continued to get all the receiver’s status in the subsequent cycles. Further, if there is no response from the specified receiver, the POLARITY (1...n) status of that receiver is modified to “reverse polarity” and the data is sent in reverse polarity (inverted data) to that receiver in the subsequent cycle. Furthermore, the central computing unit (302) is configured to maintain the polarity information and to continue polling for receivers (304, 306, 308) with their learned polarity for their responses. Once the polarity of all receivers (304, 306, 308) is discovered, the polarity discovery ends.
[0051] Figure 9 illustrates a flowchart of an adjacent polarity handling, according to an exemplary implementation of the present disclosure. Further for better utilization of communication cycles, the adjacent polarity handling is used. By adopting this method, the DATA packet reaches the destination immediately without any delay in real time. Once the receiver’s polarity is discovered as explained in Figure 8, the adjacent polarity handling of the receivers (304, 306, 308) during communication is described herein. The CCU has learnt the POLARITY (1...n) and ALIVE (1...n) receivers (304, 306, 308). If there is no DATA packet to be sent, the CCU checks for the next polled receiver’s polarity (NEXT RECEIVER) and sends only the CTRL packet (REQ) in the NEXT RECEIVER’s polarity. If a DATA packet is ready for Tx (Transmission) from CCU to a particular receiver for example, “DATA RECEIVER”, and if the next polled receiver for example, “NEXT RECEIVER”, then the CCU sends the CTRL+DATA packet (REQ) in the NEXT RECEIVER’s polarity. This CTRL+DATA packet is received by all receivers (304, 306, 308) at the same time. The receiver node i.e., NEXT RECEIVER for which the polling slot was meant will receive and process the CTRL information in the CTRL+DATA packet and respond with RESP command. The receiver node i.e., DATA RECEIVER, for which data was meant will receive and process the DATA in the CTRL+DATA packet and discard CTRL information in the CTRL+DATA packet. Assuming the DATA RECEIVER is of same polarity of NEXT RECEIVER. If the DATA RECEIVER is of opposite polarity to that of NEXT RECEIVER, then the CCU sends the CTRL+DATA packet (REQ) in the opposite polarity of the DATA RECEIVER for which the data is destined.
[0052] Figure 10 illustrates a flowchart of another embodiment of a method for determining polarity of one or more receivers over differential signal transmission in a half-duplex mode, in accordance with an embodiment of the present invention.
[0053] At step 1002, maintaining the polarity information of the one or more receivers (304, 306, 308) for polling by a central computing unit (302). In another embodiment, the central computing unit (302) is configured to maintain the polarity information of the one or more receivers (304, 306, 308) for polling.
[0054] At step 1004, initiating a data communication with one or more receivers (304, 306, 308) for a plurality of cycles by the central computing unit (302). In another embodiment, the central computing unit (302) is configured to initiate a data communication with one or more receivers (304, 306, 308) for a plurality of cycles.
[0055] At step 1006, sending a REQ command to the one or more receivers (304, 306, 308) in the first cycle by the central computing unit (302). In another embodiment, the central computing unit (302) is configured to send a REQ command to the one or more receivers (304, 306, 308) in the first cycle.
[0056] At step 1008, responding with a RESP command to the central computing unit (302) by one or more receivers (304, 306, 308), wherein the one or more receivers (304, 306, 308) are connected with same polarity. In another embodiment, the one or more receivers (304, 306, 308) are configured to respond with a RESP command to the central computing unit (302).
[0057] At step 1010, updating the polarity information of the responded receivers by the central computing unit (302). In another embodiment, the central computing unit (302) is configured to update the polarity information of the responded receivers.
[0058] At step 1012, identifying the one or more receivers (304, 306, 308) that fail to respond with a RESP command to the central computing unit (302).
[0059] At step 1014, reversing the polarity of the central computing unit (302) for sending the data to one or more receivers (304, 306, 308) connected with reverse polarity in the subsequent cycle.
[0060] At step 1016, updating the polarity information of the receivers (304, 306, 308) by the central computing unit (302)with their polarity. In another embodiment, the central computing unit (302) is configured to update the polarity information of the receivers with their polarity.
[0061] In one of the embodiments, in case, when the data from the central computing unit (302) is of positive polarity and receiver is of negative polarity, then the computing unit sends the REQ Packet in negative polarity i.e. of same polarity of the receiver node for which data is meant for and immediately without changing the state of computing unit, the REQ Packet will be sent with positive polarity i.e. of same polarity of adjacent receiver node for which the slot was assigned. Thus, the receiver node, for which data was meant for, will receive and process the data packet and discard control packet. The adjacent receiver node for which the slot was meant will process only control packet which was sent later on its same polarity. This handling ensures that the DATA packet reaches the destination immediately without any delay in real time.
[0062] In another embodiment, a method for determining polarity having a pair of differential serial transmission lines for transmitting signals in half duplex mode between a central computing unit (302) and set of receivers (304, 306, 308) is disclosed. Here, each of said receivers (304, 306, 308) has a serial interface with a pair of differential serial lines connected. This method comprises steps described herein. The central computing unit (302) is configured to initiate the communication and send REQ command to the chosen receivers (304, 306, 308) through polling, then wait for specified time for the intended receiver’s response. The receiver connected with same polarity responds with RESP command to the central computing unit (302). Further, the central computing unit (302) keeps a track of the discovered receivers (304, 306, 308) with their polarity status. Further, it assumes a receiver’s nonexistence in the network, in case if the receiver does not respond within the specified timespan. After every cycle, one undiscovered receiver gets its polling cycle again to respond. Only the receivers (304, 306, 308) that respond are discovered as they communicate with the same polarity as that of the central computing unit (302). Furthermore, to discover the receivers (304, 306, 308) connected with different polarity, the central computing unit (302) reverses its polarity (inverted data) in the subsequent alternate cycles expecting the undiscovered receivers (304, 306, 308) to respond. The central computing unit (302) is further configured to maintain the polarity information continues polling for receivers (304, 306, 308) with their learned polarity for their responses.
[0063] In another embodiment, the method wherein the central computing unit (302) is configured to keep a track of the discovered receivers (304, 306, 308) with their polarity status, further includes that when the receiver receives the control packet, it checks the destined node identifier. If destined identifier matches the identifier of the receiver node, it sends the response (RESP) control packet to the central computing unit (302). If it is not meant for the receiver node, the packet is discarded. It further includes that when the receiver receives the data packet, it checks the destined node identifier. If the destined identifier matches the identifier of the receiver node, it is processed but no response (RESP) packet is sent. If it is not meant for the receiver node, the packet is discarded.
[0064] In another embodiment, the method wherein the central computing unit (302) reverses its polarity (inverted data) in the subsequent alternate cycles, further includes that after every cycle at least a new undiscovered receiver gets its chance to be added to the network. Initially, the REQ packet sent from the computing unit is assumed to be on positive polarity. It further includes that for the next cycle for the same receiver, the REQ packet will be sent in opposite/negative polarity. Thus, discovery of new receiver node is achieved by sending the REQ packet or polling with alternate polarity in alternate cycles for that particular receiver node.
[0065] In another embodiment, the method wherein the central computing unit (302) reverses its polarity (inverted data) in the subsequent alternate cycles, further includes that in case, when the data from the central computing unit (302) is of positive polarity and receiver is of negative polarity, then the computing unit is configured to send the REQ packet in negative polarity i.e. of same polarity of the receiver node for which data is meant for and immediately without changing the state of computing unit, the REQ packet will be sent with positive polarity i.e. of same polarity of adjacent receiver node for which the slot was assigned. It further includes, the receiver node, for which data was meant for, will receive and process the data packet and discard control packet. The adjacent receiver node for which the slot was meant will process only control packet which was sent later on its same polarity.
[0066] In another embodiment, the serial signal transmission uses two transmission wires, for communication, by transmitting data via differential signals. The receivers (304, 306, 308) can be connected to the - central computing unit (302) with either polarity i.e. same or opposite polarity with respect to the central computing unit (302). The communication succeeds only in same polarity. For devices connected with opposite polarity, requires polarity switching at central computing unit (302). This polarity switching can be either a hardware or software solution. This method handles the communication between central computing unit (302) and receivers (304, 306, 308) with mixed polarity in serial signal transmission channel. The receivers (304, 306, 308) are simple processing devices with standard serial signal transmit/receive chip incorporated to handle polarity switching. The software at the central computing unit (302) is configured to determine the polarity and extend the communication protocols which is used to communicate between central computing unit (302) and many receivers (304, 306, 308), thus with no inversion logic at the receivers (304, 306, 308). It is also configured to handle dynamic switching of polarity of receivers (304, 306, 308) during live communication.
[0067] In another embodiment, the method disclosed herein provides a method for achieving polarity discovery. Due to the differential voltage data transmission, the data transmitted on one line is exactly of opposite polarity on another line and vice versa. If some of the receivers (304, 306, 308) are connected opposite to that of central computing unit (302) polarity, then it is said to be connected on reverse polarity. The communication at the central computing unit (302) involves the steps of discovering the polarity of the receivers (304, 306, 308) and saving the receivers (304, 306, 308) polarity status in connectivity structure.
[0068] The foregoing description of the invention has been set merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to person skilled in the art, the invention should be construed to include everything within the scope of the invention.
,CLAIMS:
1. A method for determining polarity of one or more receivers (304, 306, 308) over differential signal transmission in a half-duplex mode, said method comprising:
maintaining, by a central computing unit (302), the polarity information of the one or more receivers (304, 306, 308) for polling;
initiating, by the central computing unit (302), a data communication with one or more receivers (304, 306, 308) for a plurality of cycles;
sending, by the central computing unit (302), a REQ command to the one or more receivers (304, 306, 308) in the first cycle;
responding, by one or more receivers (304, 306, 308), with a RESP command to the central computing unit (302), wherein the one or more receivers (304, 306, 308) are connected with same polarity;
updating, by the central computing unit (302), the polarity information of the responded receivers;
identifying the one or more receivers (304, 306, 308) that fail to respond with a RESP command to the central computing unit (302);
reversing the polarity of the central computing unit (302) for sending the data to one or more receivers (304, 306, 308) connected with reverse polarity in the subsequent cycle; and
updating, by the central computing unit (302), the polarity information of the receivers (304, 306, 308) with their polarity.

2. The method as claimed in claim 1, wherein the one or more receivers (304, 306, 308) includes first receiver (304) and the second receiver (306).

3. The method as claimed in claim 1, wherein the one or more receivers (304, 306, 308) are selected through polling before sending the REQ command to one or more receivers (304, 306, 308) in the first cycle.

4. The method as claimed in claim 1 and claim 2, said method further includes:
managing the polarity of the adjacent one or more receivers (304, 306, 308), said managing further includes:
verifying, by the central computing unit (302), the polarity of the second receiver (306) if no data is to be sent;
sending the REQ command in the second receiver’s (306) polarity;
verifying the availability of the data for transmitting from the central computing unit (302) to the first receiver (304);
sending the data and the REQ command in the first receiver’s (304) polarity;
receiving and processing, by the first receiver (304), the data from the sent data and the REQ command;
discarding, by the first receiver (304), the REQ command as it is meant for the second receiver;
sending the data and REQ command in the second receiver’s (306) polarity;
receiving and processing, by the second receiver (306), the REQ command from the sent data and the REQ command; and
responding, by the second receiver (306), with RESP command.

5. The method as claimed in claim 1, said method further includes a pair of differential serial transmission lines for transmitting signals in the half duplex mode between a central computing unit (302) and one or more receivers (304, 306, 308), wherein each of the receivers (304, 306, 308) has a serial interface with the connected pair of differential serial lines transmission.

6. The method as claimed in claim 1, wherein sending the REQ command to one or more receivers (304, 306, 308) in the first cycle further includes:
verifying, by the central computing unit (302), the destined node identifier once said receiver receives the REQ command;
responding, by the receiver, with a RESP command to the central computing unit (302) once the destined node identifier matches with the identifier of the receiver; and
discarding the REQ command when the destined node identifier fails to match with the identifier of the receiver.

7. The method as claimed in claim 1, wherein the REQ command sent to the receiver in the first cycle is of positive polarity, said REQ command is sent in negative polarity in the subsequent cycle for said receiver for detecting another receiver.

8. A system for determining polarity of one or more receivers (304, 306, 308) over differential signal transmission in a half-duplex mode, said system comprising:
a memory;
a central computing unit (302) coupled with the memory, the central computing unit (302) configured to:
maintain the polarity information of the one or more receivers (304, 306, 308) for polling;
initiate a data communication with one or more receivers (304, 306, 308) for a plurality of cycles;
send a REQ command to the one or more receivers (304, 306, 308) in the first cycle;
the one or more receivers (304, 306, 308) configured to respond with a RESP command to the central computing unit (302), wherein the one or more receivers (304, 306, 308) are connected with same polarity;
the central computing unit (302) configured to update the polarity information of the responded receivers;
identify the one or more receivers (304, 306, 308) that fail to respond with a RESP command to the central computing unit (302);
reverse the polarity of the central computing unit (302) for sending the data to one or more receivers (304, 306, 308) connected with reverse polarity in the subsequent cycle; and
the central computing unit (302) configured to update the polarity information of the receivers with their polarity.